Despite the hype surrounding VoIP and the technology's proven benefits, some organizations are still taking baby steps toward converged networking.

One such outfit is Baptist Health Medical Center in the US, which has 8,000 phones, but only 240 IP ones.

"I just can't see us going up on one floor and saying we're taking out all of the TDM phones and putting in IP," says John Myers, convergence analyst at the medical center. "To go in and change everything out just to be changing it just doesn't make sense."

That's even though Myers is well aware of what VoIP promises: A converged, cost-efficient infrastructure and new productivity-increasing applications. There are no shortage of early adopters, from Bank of America to Black and Decker, which laud the benefits of VoIP and unified communications.

The trends are clear: In 2007, IP PBX revenue grew 29 per cent to US$1.6 billion and line shipments grew 32 per cent, according to Dell'Oro. Dell'Oro expects IP lines to surpass digital and analog PBX lines for the first time by year-end. By contrast, TDM PBX revenue declined 20 per cent to about US$1 billion in 2007, Dell'Oro found.

Still, Baptist Health says a measured transition to VoIP makes the most sense for it, and there are lessons to be learned from its approach.

Most of Baptist Health's 8,000 phones are located in a 15-floor building, but the medical center has eight sites overall. As it moves offices or builds new facilities, it will outfit those desktops with IP phones, Myers says.

"We never made a decision to forklift everything out and replace it with IP, but as departments moved or are added or if we buy up a clinic across town -- if we feel it's a good candidate for IP that's what we do," he says.

Baptist Health's slow move to VoIP began with a 15-phone trial two years ago. The medical center is predominantly a Nortel shop and it deploys the vendor's Communications Server 1000 IP PBXes and 1140E IP phones, as well as its analog and digital PBXes and phones.

The hospital embarked on its VoIP quest in an effort to reduce cost. Myers figures the medical center can save money on expense of cabling new facilities by running voice over the IP data network instead of nailing up a separate voice network every time a department moves or is added.

"We built a brand-new hospital last year and put half of the phones in that facility as IP," Myers says. "We were able to drop one cable, plug the phone in there and run the PC off the back of the phone. That's the biggest thing for us."

The 1140E phone includes a Gigabit Ethernet PC port on the back.

Myers also says the VoIP phones are easier to manage because he can monitor them from a central location with the tools he uses for the data network instead of performing onsite maintenance and troubleshooting of the medical center's traditional PBXes.

But so far, cost savings have been hard to quantify given that only a fraction of the health center's phones are IP. Also, the IP phones are significantly more expensive than the traditional TDM phones, he says.

The average sales price of an IP phone at the end of 2007 was between US$150 and $200, according to Dell'Oro. Meanwhile, a basic TDM business phone can cost as little as US$20.